Gamers discovered a clever feature in the newest 'Super Mario' game that turns it into a musical instrument

You can do a lot of things in "Super Mario Maker," the new game
from Nintendo starring the ever-mustachioed Super Mario. You can
create levels across four distinct Super Mario universes: the
original "Super Mario Bros.," "Super Mario Bros. 3," "Super Mario
World," and "New Super Mario Bros. U." You can upload your levels
to the internet for anyone to play. You can play levels from all
four universes created by people all over the world. Nintendo
itself even created a grip of levels for you to enjoy.

So, what are players doing with the toolset provided by
Nintendo? Amazing things, as evidenced by these
five levels full of game-created tunes.

Wondering how it all happens? It's the music blocks! These guys:

Nintendo

As Mario rolls along on the motorized track, the music blocks
above pluck out the theme for Game Boy classic "Super Mario
Land" (which is quite a catchy tune!).

These levels have become especially popular in the early days of
"Super Mario Maker," which launched on September 11 for the
Nintendo Wii U. It's easy to understand why: they're simple,
interesting, and filled with nostalgia (as if the game wasn't
already packed to the gills with nostalgia).

But despite the seeming simplicity of these levels, creating them
is amazingly complex. You can't just program a music block
to produce a desired note. The blocks only create a note
when they're interacted with; the pitch of that note is dictated
by where it's placed on-screen. Here's
a helpful chart from GameFAQ explaining the system:

Nintendo

As the pirahna plants fall, they interact with the music notes.
To create timing for how these notes will play, you need to force
consistency in movement on the level. One such solution is
putting constantly moving tracks at the bottom of the level
(which keeps Mario in movement). Another such solution is forcing
Mario to run full speed throughout the whole level in order to
survive.

In both cases, the goal is to keep Mario in a constant state of
movement, thus providing a consistent time signature. Think of it
like a record player that runs at a constant speed, thus
providing a consistent rate of music. Except, instead of a record
player, it's a little Italian plumber trying not to fall to his
death.